Weighing and testing apparatus of the steelyard type



Sept; 1930- F. w. HIGHFIELD 8 WEIGHING AND TES TING APPARATUS OF THESTEELYARD TYPE Filed Jui 16, 1928 jw e/v Ta 12 Patented Sept. 16, 1930 Hi i v i UNITED STATES PATENT OFFICE FRANK WOOTTON' HIGHFIELD, OFCOVENTRY, ENGLAND WEIGHING AND TESTING APPARATUS OF THE STEELYARI) TYPEApplication filed July 16, 1828, Serial No. 292,977, and in GreatBritain July 22, 1927.

This invention relates to weighing and verse direction. When the stateof balance testing apparatus of the steelyard type in is obtained, thecontact is occupies a neutral which a load is counterbalanced by aweight or intermediate position. The load is apwhich is capable of beingmoved along a plied to the beam through the link n. Any

beam or lever. The invention is applicable suitable electricalconnections may be em- 55 to various forms of weighing machines,maployed in the circuit of the motor 7'. For chines for testingmaterials, such as tensile example, as shown, one end of the circuittesting machines, and dynamo-meters emcontaining the motor is attachedto is, and ployed for the testing of prime movers. the other end to thejunction of a pair of 10 The object of the invention is to provideresistances r. The opposite ends of the 60 automatic electrical meansfor indicating the latter are respectively connected to the conconditionof balance. tacts is, Z, and a current supply terminal.

The invention comprises the combination The resistance It may form partof a with the beam or the like and the sliding WVheatstone bridge systemcontaining a weight, of an electric circuit containing any galvanometer.Alternatively the resistance 65 suitable indicating instrument thereading it may form part of a potentiometer or other of which iscontrolled by and corresponds suitable system containing an ohmmeter orwith the position of the weight. other convenient indicator. In eithercase,

' The accompanying drawing illustrates the indicating instrument isgraduated to diagrammatically one manner of applying indicate theposition of the weight on the 70 the invention to a steelyard typemachine. beam at any instant. The direction of Referring to the diagram,the beam is movement of the instrument also indicates ind cated by a.This is pivoted at b and is the direction in which the weight ismovloaded at the other end by weights 0. The ing. In the exampleillustrated a potenbeam is provided with the usual sliding tiometer isused. The ends of h are con- 15 Weight 01 which may be provided with anected to any convenient source of current pointer e travelling over afixed graduated at the terminals 8, whilst the contact 9 is scale 7. Incombination with the weight is connected through the indicatinginstruarranged a moving contact piece 9 insulated ment zto one end ofthe potentiometer.

from the beam which can travel along a re The invention is particularlyuseful in so sistance h. The latter may be of any conconjunction withdynamometers for testing venient type, for example, a helical wirereprime movers, but it is applicable also to sist-ance wound on asuitable rigid core. ordinary weighing machines, or machines The Weightis caused to move along the beam for testing materials, or for otheranalogous by means of a screw 2' which can be rotated purposes in whichapparatus of the steelyard 85 through any convenient mechanism by typeis employed. means of a small electric motor j carried on The inventionis not limited to any parone end of the beam. The electric motor isticular mechanical or electrical details, as controlled by a movablecontact 7r: carried these may be varied to meet different requireat thefree end of the beam. This contact Inents. 9o

co-operates with a pair of fixed contacts Z, Having thus described myinvention what m maintained at a suitable difference of elec I claim asnew and desire to secure by Lettric potential situated at the upper andters Patent is zlower limits of the movement of the beam. In weighingand testing apparatus of the 4 The arrangement of the motor circuit andsteelyard type, the combination comprising at of the contacts is, Z, mis such that when a pivoted beam, a sliding weight, an electric thecontact touches the contact Z, the mocircuit consisting in part of aresistance artor drives the screw in one direction, whilst ranged inpart on the beam, a contact on the when the contact Z touches thecontact m, weight co-operating with said resistance on 50 the screw isdriven by the motor in the rethe beam, an electrical indicating instru-FRANK WOOTTON HIGH'FIELD.

